Canadian Underwriter

Voice-to-text e-mail causes ‘significant impairment’ to driving: study

June 12, 2013   by Canadian Underwriter

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The AAA Foundation For Traffic Safety announced Wednesday the publication a study on what it calls “cognitive sources of distraction” during driving.


The study, sponsored by the foundation, suggests that text-to-speech e-mail can impair driving even though the drivers don’t have to take their eyes off the road or their hands off the wheel.

It defines “cognitive sources of distraction” as those that occur when drivers withdraw their attention from the processing of information necessary for the safe operation of a motor vehicle.

The experiments measured driver performance in tasks such as listening to a radio, listening to a book on tape, talking to a passenger, talking on a hands-free cellphone, and talking on a handheld cellphone, as well as using text-to-speech e-mail. It compared their performance to a baseline study where none of these distractions were present.

The results of the experiments were published in a paper titled Measuring Cognitive Distraction in the Automobile, whose authors included David Strayer, a professor of psychology at the University of Utah in Salt Lake City.

“We established that there are significant impairments to driving that stem from the diversion of attention from the task of operating a motor vehicle, and that the impairments to driving are directly related to the cognitive workload of these in-vehicle activities,” the study concluded.

“Moreover, compared to the other activities studied (e.g., listening to the radio, conversing with passengers, etc.) we found that interacting with the speech-to-text system was the most cognitively distracting. This clearly suggests that the adoption of voice-based systems in the vehicle may have unintended consequences that adversely affect traffic safety.”

In the experiments, the researchers measured brainwaves and eye movement assess drivers’ mental workload.

“A Detection-Response-Task device known as the ‘DRT’ was used to record driver reaction time in response to triggers of red and green lights added to their field of vision,” the Washington, D.C.-based AAA Foundation For Traffic Safety stated in a press release. “A special electroencephalographic (EEG)-configured skull cap was used to chart participants’ brain activity so that researchers could determine mental workload.”

The foundation added it has provided the study results to the chief executive officers of major auto manufacturers.

“AAA is hopeful that it will serve as a stepping stone toward working in collaboration with automakers to promote our shared goal of improving safety for all drivers,” AAA President and CEO Robert Darbelnet stated in a press release.

“Specifically, these increasingly common voice-driven, in-vehicle technologies should be limited to use for just core driving tasks unless the activity results in no significant driver distraction.”

AAA suggested it is using the results to “promote dialogue” with regulators, as well as the auto and electronics industries.

The experiments were conducted on 20 men and 18 women, ranging in age from 18 to 30, recruited from the University of Utah. Their driving experience “ranged from 2.5 to 14.5, with an average of 6.9 years.”

One of the experiments took place in a driving simulator, where participants were asked to follow two seconds behind a pace car that braked periodically. The researchers collected data such as brake reaction time and following distance.

“Brake reaction time to imperative events in the driving simulator systematically increased as a function of the cognitive workload associated with performing the different in-vehicle activities,” the study reported.

In another experiment, the subjects were asked to drive a real car through a residential area. A research assistant had access to a redundant braking system and cameras recorded eye movements to see if participants checked their side mirrors, rear view mirrors and dashboard.

“Our research establishes that that there is a systematic decrease in scanning for hazards as cognitive workload increases,” according to the paper.